Both the CLIST language and the REXX language can be used in TSO/E as procedures languages. Some major features of REXX that are different from CLIST are:

• Host command environments - TSO/E REXX has the ability to invoke commands from several environments in MVS™ and ISPF, as well as from TSO/E. The ADDRESS instruction sets the environment for commands. For more information, see Issuing Other Types of Commands from an Exec.
• Parsing capabilities - For separating data into variable names and formatting text, REXX provides extensive parsing through templates. For more information, see Parsing Data.
• Use of a data stack - REXX offers the use of a data stack in which to store data. For more information, see Storing Information in the Data Stack.
• Use of mixed and lowercase characters - Although variables and most input are translated to uppercase, REXX provides ways to maintain mixed and lowercase representation. For more information, see Preventing Translation to Uppercase.

In some ways CLIST and REXX are similar. The following tables show similarities and differences in the areas of:

• Accessing system services
• Controlling program flow
• Debugging
• Execution
• Interactive communication
• Passing information
• Performing file I/O
• Syntax
• Using functions
• Using variables